Sierra 18-5405 Ignition Rotor for MerCruiser 350 MAG MPI V-8, GM Module-in-Cap Distributors

The Sierra 18-5405 is an ignition distributor rotor built for GM-style "module in cap" V-8 distributor applications, including MerCruiser 350 MAG MPI engines equipped with contact-controlled distributors running standard rotation (this rotor does not apply to Thunderbolt ignition systems). The rotor is the component inside the distributor cap that spins with the distributor shaft to route the high-voltage spark from the ignition coil to the correct spark plug wire terminal in firing order, so its fit and contact geometry directly affect spark timing and engine reliability.

Finished in white, the rotor measures 3 x 2 x 2 inches and weighs 0.06 pounds, making it a compact, easy-to-stock replacement part for a tune-up or distributor cap and rotor service. It is manufactured to meet or exceed the specifications of the original equipment part it replaces, and is commonly paired with a matching distributor cap, contact set, and ignition coil when performing a full ignition tune-up on covered engines.

This rotor is confirmed for MerCruiser 350 MAG MPI (GEN +) 350 cid V-8 engines, model year 1998 within serial number range L010019-L325962; 350 MAG MPI MIE (GEN +) 350 cid V-8 engines, model year 1998 within serial number range L002008-L302199; and 350 MAG MPI SKI 350 cid V-8 engines, model years 1995-1998 within serial number range F350583-L304599.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-5405
• UPC: 030999563729
• Item Dimensions (L x W x H): 3 x 2 x 2 inches
• Weight: 0.06 pounds
• Color: White
• Quantity: 1 rotor
• Ignition System Type: Contact controlled distributor, standard rotation, excludes Thunderbolt ignition
• Distributor Style: GM style module in cap, V-8 application

Fitment

• MerCruiser 350 MAG MPI (GEN +) 350/V-8, 1998, Serial L010019-L325962
• MerCruiser 350 MAG MPI MIE (GEN +) 350/V-8, 1998, Serial L002008-L302199
• MerCruiser 350 MAG MPI SKI 350/V-8, 1995-1998, Serial F350583-L304599

Replaces (OEM)

• Crusader 38071
• GLM 71100
• Mallory 9-29209
• Mercruiser 898253010
• Mercruiser 808484-1
• Mercruiser 804423
• Mercruiser 8M6001253
• OMC 3854549
• Volvo Penta 3854549-7
• Volvo Penta 3862014

Frequently Asked Questions

What is the Sierra 18-5405 rotor used for? The Sierra 18-5405 is an ignition distributor rotor that mounts inside the distributor cap and routes spark from the coil to each spark plug wire terminal in firing order, and it is designed for GM style module in cap V-8 distributors.

Will the 18-5405 rotor fit my MerCruiser 350 MAG MPI? Yes, on the 350 MAG MPI (GEN +) 350/V-8 built in 1998 within serial number range L010019-L325962, and on the 350 MAG MPI MIE (GEN +) 350/V-8 also built in 1998 within serial number range L002008-L302199 - check your engine serial number against these ranges before ordering.

Does the 18-5405 rotor work on MerCruiser 350 MAG MPI SKI engines? Yes, the Sierra 18-5405 covers the 350 MAG MPI SKI 350/V-8, model years 1995-1998, within serial number range F350583-L304599.

Does this rotor work with Thunderbolt ignition systems? No, the Sierra 18-5405 is built for contact controlled distributors with standard rotation and specifically excludes Thunderbolt ignition applications.

What OEM part numbers does the 18-5405 rotor replace? It is interchangeable with Crusader 38071, GLM 71100, Mallory 9-29209, Mercruiser 898253010, 808484-1, and 804423, 8M6001253, OMC 3854549, and Volvo Penta 3854549-7 and 3862014.

What color and material is the 18-5405 rotor? The rotor is white and is sized at 3 x 2 x 2 inches, weighing 0.06 pounds.

Is the Sierra 18-5405 a genuine OEM part or an aftermarket replacement? It is an aftermarket replacement rotor manufactured by Sierra to meet or exceed the specifications of the original equipment rotor it replaces.

How many rotors come in a package of the 18-5405? One Sierra 18-5405 rotor is included per package.

What type of distributor does the 18-5405 rotor fit? It fits GM style module in cap distributors used in V-8 applications, specifically contact controlled distributors running standard rotation.

Should I replace the distributor cap at the same time as the 18-5405 rotor? During a full ignition tune-up, the rotor is commonly replaced alongside the distributor cap, contact set, and coil to restore complete ignition performance, though the 18-5405 itself is sold as the rotor only.